1/*
2 * net/sched/ipt.c	iptables target interface
3 *
4 *TODO: Add other tables. For now we only support the ipv4 table targets
5 *
6 *		This program is free software; you can redistribute it and/or
7 *		modify it under the terms of the GNU General Public License
8 *		as published by the Free Software Foundation; either version
9 *		2 of the License, or (at your option) any later version.
10 *
11 * Copyright:	Jamal Hadi Salim (2002-4)
12 */
13
14#include <linux/types.h>
15#include <linux/kernel.h>
16#include <linux/string.h>
17#include <linux/errno.h>
18#include <linux/skbuff.h>
19#include <linux/rtnetlink.h>
20#include <linux/module.h>
21#include <linux/init.h>
22#include <linux/slab.h>
23#include <net/netlink.h>
24#include <net/pkt_sched.h>
25#include <linux/tc_act/tc_ipt.h>
26#include <net/tc_act/tc_ipt.h>
27
28#include <linux/netfilter_ipv4/ip_tables.h>
29
30
31#define IPT_TAB_MASK     15
32static struct tcf_common *tcf_ipt_ht[IPT_TAB_MASK + 1];
33static u32 ipt_idx_gen;
34static DEFINE_RWLOCK(ipt_lock);
35
36static struct tcf_hashinfo ipt_hash_info = {
37	.htab	=	tcf_ipt_ht,
38	.hmask	=	IPT_TAB_MASK,
39	.lock	=	&ipt_lock,
40};
41
42static int ipt_init_target(struct ipt_entry_target *t, char *table, unsigned int hook)
43{
44	struct xt_tgchk_param par;
45	struct xt_target *target;
46	int ret = 0;
47
48	target = xt_request_find_target(AF_INET, t->u.user.name,
49					t->u.user.revision);
50	if (IS_ERR(target))
51		return PTR_ERR(target);
52
53	t->u.kernel.target = target;
54	par.table     = table;
55	par.entryinfo = NULL;
56	par.target    = target;
57	par.targinfo  = t->data;
58	par.hook_mask = hook;
59	par.family    = NFPROTO_IPV4;
60
61	ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
62	if (ret < 0) {
63		module_put(t->u.kernel.target->me);
64		return ret;
65	}
66	return 0;
67}
68
69static void ipt_destroy_target(struct ipt_entry_target *t)
70{
71	struct xt_tgdtor_param par = {
72		.target   = t->u.kernel.target,
73		.targinfo = t->data,
74	};
75	if (par.target->destroy != NULL)
76		par.target->destroy(&par);
77	module_put(par.target->me);
78}
79
80static int tcf_ipt_release(struct tcf_ipt *ipt, int bind)
81{
82	int ret = 0;
83	if (ipt) {
84		if (bind)
85			ipt->tcf_bindcnt--;
86		ipt->tcf_refcnt--;
87		if (ipt->tcf_bindcnt <= 0 && ipt->tcf_refcnt <= 0) {
88			ipt_destroy_target(ipt->tcfi_t);
89			kfree(ipt->tcfi_tname);
90			kfree(ipt->tcfi_t);
91			tcf_hash_destroy(&ipt->common, &ipt_hash_info);
92			ret = ACT_P_DELETED;
93		}
94	}
95	return ret;
96}
97
98static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
99	[TCA_IPT_TABLE]	= { .type = NLA_STRING, .len = IFNAMSIZ },
100	[TCA_IPT_HOOK]	= { .type = NLA_U32 },
101	[TCA_IPT_INDEX]	= { .type = NLA_U32 },
102	[TCA_IPT_TARG]	= { .len = sizeof(struct ipt_entry_target) },
103};
104
105static int tcf_ipt_init(struct nlattr *nla, struct nlattr *est,
106			struct tc_action *a, int ovr, int bind)
107{
108	struct nlattr *tb[TCA_IPT_MAX + 1];
109	struct tcf_ipt *ipt;
110	struct tcf_common *pc;
111	struct ipt_entry_target *td, *t;
112	char *tname;
113	int ret = 0, err;
114	u32 hook = 0;
115	u32 index = 0;
116
117	if (nla == NULL)
118		return -EINVAL;
119
120	err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy);
121	if (err < 0)
122		return err;
123
124	if (tb[TCA_IPT_HOOK] == NULL)
125		return -EINVAL;
126	if (tb[TCA_IPT_TARG] == NULL)
127		return -EINVAL;
128
129	td = (struct ipt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
130	if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size)
131		return -EINVAL;
132
133	if (tb[TCA_IPT_INDEX] != NULL)
134		index = nla_get_u32(tb[TCA_IPT_INDEX]);
135
136	pc = tcf_hash_check(index, a, bind, &ipt_hash_info);
137	if (!pc) {
138		pc = tcf_hash_create(index, est, a, sizeof(*ipt), bind,
139				     &ipt_idx_gen, &ipt_hash_info);
140		if (IS_ERR(pc))
141		    return PTR_ERR(pc);
142		ret = ACT_P_CREATED;
143	} else {
144		if (!ovr) {
145			tcf_ipt_release(to_ipt(pc), bind);
146			return -EEXIST;
147		}
148	}
149	ipt = to_ipt(pc);
150
151	hook = nla_get_u32(tb[TCA_IPT_HOOK]);
152
153	err = -ENOMEM;
154	tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
155	if (unlikely(!tname))
156		goto err1;
157	if (tb[TCA_IPT_TABLE] == NULL ||
158	    nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
159		strcpy(tname, "mangle");
160
161	t = kmemdup(td, td->u.target_size, GFP_KERNEL);
162	if (unlikely(!t))
163		goto err2;
164
165	if ((err = ipt_init_target(t, tname, hook)) < 0)
166		goto err3;
167
168	spin_lock_bh(&ipt->tcf_lock);
169	if (ret != ACT_P_CREATED) {
170		ipt_destroy_target(ipt->tcfi_t);
171		kfree(ipt->tcfi_tname);
172		kfree(ipt->tcfi_t);
173	}
174	ipt->tcfi_tname = tname;
175	ipt->tcfi_t     = t;
176	ipt->tcfi_hook  = hook;
177	spin_unlock_bh(&ipt->tcf_lock);
178	if (ret == ACT_P_CREATED)
179		tcf_hash_insert(pc, &ipt_hash_info);
180	return ret;
181
182err3:
183	kfree(t);
184err2:
185	kfree(tname);
186err1:
187	kfree(pc);
188	return err;
189}
190
191static int tcf_ipt_cleanup(struct tc_action *a, int bind)
192{
193	struct tcf_ipt *ipt = a->priv;
194	return tcf_ipt_release(ipt, bind);
195}
196
197static int tcf_ipt(struct sk_buff *skb, struct tc_action *a,
198		   struct tcf_result *res)
199{
200	int ret = 0, result = 0;
201	struct tcf_ipt *ipt = a->priv;
202	struct xt_action_param par;
203
204	if (skb_cloned(skb)) {
205		if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
206			return TC_ACT_UNSPEC;
207	}
208
209	spin_lock(&ipt->tcf_lock);
210
211	ipt->tcf_tm.lastuse = jiffies;
212	ipt->tcf_bstats.bytes += qdisc_pkt_len(skb);
213	ipt->tcf_bstats.packets++;
214
215	/* yes, we have to worry about both in and out dev
216	 worry later - danger - this API seems to have changed
217	 from earlier kernels */
218	par.in       = skb->dev;
219	par.out      = NULL;
220	par.hooknum  = ipt->tcfi_hook;
221	par.target   = ipt->tcfi_t->u.kernel.target;
222	par.targinfo = ipt->tcfi_t->data;
223	ret = par.target->target(skb, &par);
224
225	switch (ret) {
226	case NF_ACCEPT:
227		result = TC_ACT_OK;
228		break;
229	case NF_DROP:
230		result = TC_ACT_SHOT;
231		ipt->tcf_qstats.drops++;
232		break;
233	case IPT_CONTINUE:
234		result = TC_ACT_PIPE;
235		break;
236	default:
237		if (net_ratelimit())
238			pr_notice("tc filter: Bogus netfilter code"
239				  " %d assume ACCEPT\n", ret);
240		result = TC_POLICE_OK;
241		break;
242	}
243	spin_unlock(&ipt->tcf_lock);
244	return result;
245
246}
247
248static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
249{
250	unsigned char *b = skb_tail_pointer(skb);
251	struct tcf_ipt *ipt = a->priv;
252	struct ipt_entry_target *t;
253	struct tcf_t tm;
254	struct tc_cnt c;
255
256	/* for simple targets kernel size == user size
257	** user name = target name
258	** for foolproof you need to not assume this
259	*/
260
261	t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
262	if (unlikely(!t))
263		goto nla_put_failure;
264
265	c.bindcnt = ipt->tcf_bindcnt - bind;
266	c.refcnt = ipt->tcf_refcnt - ref;
267	strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
268
269	NLA_PUT(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t);
270	NLA_PUT_U32(skb, TCA_IPT_INDEX, ipt->tcf_index);
271	NLA_PUT_U32(skb, TCA_IPT_HOOK, ipt->tcfi_hook);
272	NLA_PUT(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c);
273	NLA_PUT_STRING(skb, TCA_IPT_TABLE, ipt->tcfi_tname);
274	tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install);
275	tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse);
276	tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires);
277	NLA_PUT(skb, TCA_IPT_TM, sizeof (tm), &tm);
278	kfree(t);
279	return skb->len;
280
281nla_put_failure:
282	nlmsg_trim(skb, b);
283	kfree(t);
284	return -1;
285}
286
287static struct tc_action_ops act_ipt_ops = {
288	.kind		=	"ipt",
289	.hinfo		=	&ipt_hash_info,
290	.type		=	TCA_ACT_IPT,
291	.capab		=	TCA_CAP_NONE,
292	.owner		=	THIS_MODULE,
293	.act		=	tcf_ipt,
294	.dump		=	tcf_ipt_dump,
295	.cleanup	=	tcf_ipt_cleanup,
296	.lookup		=	tcf_hash_search,
297	.init		=	tcf_ipt_init,
298	.walk		=	tcf_generic_walker
299};
300
301MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
302MODULE_DESCRIPTION("Iptables target actions");
303MODULE_LICENSE("GPL");
304
305static int __init ipt_init_module(void)
306{
307	return tcf_register_action(&act_ipt_ops);
308}
309
310static void __exit ipt_cleanup_module(void)
311{
312	tcf_unregister_action(&act_ipt_ops);
313}
314
315module_init(ipt_init_module);
316module_exit(ipt_cleanup_module);
317